With her head tilted to the right, her hazel eyes are cast downward in an expression of gentleness and concern. The mantle covering her head and shoulders is turquoise, studded with gold stars and bordered in gold. Her hair is jet black and her complexion is olive. She stands alone, her hands clasped in prayer, an angel at her feet.

We have all seen her image. She is Our Lady of Guadalupe, a life-sized portrayal of the Virgin Mary as she appeared in 1531 on the cactus-cloth tilma, or cape, of St. Juan Diego, an Aztec peasant and devout convert. This happened merely a dozen years after Hernan Cortes had conquered the land that is now Mexico for the monarchy of Spain. Almost five centuries later the colors of that portrait have remained as vibrant as if painted this year. The coarse, woven, cactus cloth shows no signs of fading or deterioration, although that type of material seldom lasts 20 years.

Today the image is preserved behind an impenetrable glass screen in the basilica at Mexico City. Pilgrims can view it from a distance of 25 feet. Each year more than 10 million persons venerate the mysterious image of the Virgin of Guadalupe, making this shrine the most popular in the Catholic world after St. Peter’s Basilica at Vatican City. The Mexican faithful refer to her lovingly as La Morenita.

In 1979 when Pope John Paul II visited the Basilica of Our Lady of Guadalupe, he acknowledged the enduring appeal of this unique portrait, addressing the Virgin directly: “When the first missionaries who reached America . . . taught the rudiments of the Christian faith, they also taught love for you, the Mother of Jesus and of all people. And ever since the time that the Indian Juan Diego spoke of the sweet Lady of Tepeyac, you, Mother of Guadalupe, have entered decisively into the Christian life of the people of Mexico.”

Accounts abound of the miraculous events attributed to the Virgin of Guadalupe. In the early 17thcentury when floods almost destroyed Mexico City, her image escaped unharmed. In 1921 during the Mexican Revolution, a bomb was planted in flowers placed before the altar behind which the image hung. When the bomb exploded, no one was hurt, but the altar was badly damaged. Yet not even the glass covering the picture was broken.

This venerable icon has come to be regarded widely as the national symbol of Mexico. Her image is found everywhere, even in unlikely places.

Forty years after La Morenita appeared to St. Juan Diego, she may have been responsible for a significant turning point in the history of Western civilization. Throughout Europe copies of the holy image had been circulated. One of the first copies was given to Admiral Giovanni Andrea Doria, grandnephew of the renowned Admiral Andrea Doria. The young admiral took the picture aboard his flagship when he assumed command of a flotilla of ships sailing fromGenoa to the Gulf of Lepanto.

Some 300 Turkish Muslim ships stood in battle array blocking entrance to the Gulf. A Christian massed navy of almost the same number of ships attempted to meet the Turks head on, but were outmaneuvered by the Turkish force.

Doria’s squadron was cut off from the rest of the Christian fleet. At this crucial hour Doria went to his cabin and knelt in prayer before the image of Our Lady of Guadalupe. He implored her to save his men and his ships. Miraculously by nightfall the tide of battle turned. One Turkish squadron was captured, and others were thrown into panic and disarray. Much of the Turkish fleet was destroyed. That day 15,000 Christians enslaved in the Turks’ galleys were freed. The Christian victory in the Battle of Lepanto was the last great naval battle fought under oars.

To this day Our Lady of Guadalupe continues to work wonders large and small, noticed and unnoticed.

Why hasn’t the holy image deteriorated after almost five centuries? Why do the colors remain bright? Why hasn’t the crude fabric shown signs of disintegration? The search for answers to these questions, regularly pursued by experts, persists from generation to generation. What they have learned is fascinating. However, the scientific investigations defy natural explanations.

Although the picture has been touched up from time to time, there is proof that the original image is made in a manner no artist has been able to imitate or to explain. Of particular interest is the fact that the eyes of the Virgin are done in a way never seen before in any painting.

Yet the greater, ongoing miracle is how the lives of millions are touched by Our Mother of Guadalupe.